Laser welding: An alternative method of venous repair (original) (raw)
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Biological effects of laser welding on vascular healing
Lasers in Surgery and Medicine, 1986
The feasibility of welding thin-walled microvessels by laser has been established. This report summarizes our experience using laser welding to repair thick-walled, high-pressure, 4 to 8-mm canine arteries using C02, Nd:YAG, and argon lasers. The C02 laser did not produce seals that could withstand arterial pressure. Nd:YAG laser welds were initially successful, but the majority failed within 20 to 40 minutes. The argon laser uniformly sealed 2-cm-length arteriotomies that healed rapidly within 4 to 6 weeks and had less foreign body response compared to sutured controls. Laser welding may represent an alternative for repair of smalland largediameter vessels with several advantages compared to conventional suture techniques.
Mechanism of tissue fusion in argon laser-welded vein-artery anastomoses
Lasers in Surgery and Medicine, 1988
The mechanism of laser vascular tissue welding remains unknown. This study compared the acute tissue response and long-term healing of sutured and laser-welded anastomoses of vein segments used to bypass ligated canine femoral arteries. For each procedure, one anastomosis was formed using running 6-0 polypropylene suture (control), and the other anastomosis was formed using argon laser tissue welding (experimental). The vein grafts were harvested at 4 (n = 2), 8 (n = l), 12 (n = l), and 16 (n = 2) weeks, and selected samples were evaluated by histologic examination, electron microscopy, tensile strength testing, and by measuring the formation of [3H]hydroxyproline as an index of collagen synthesis. Examination of successful laser fusions immediately after they were formed showed bonding of collagen to collagen and elastin to collagen. Follow-up evaluations showed that the precision of tissue apposition affected the rate of healing and tensile strength. Laser-welded anastomoses demonstrated a progression of healing similar to sutured repairs, with remodeling of fibrous tissue and collagen being the primary component of weld integrity. This study demonstrates that sutured and argon laser-welded vein-artery anastomoses heal comparably up to 16 weeks postoperatively, and that laser welding is a satisfactory alternative to sutured anastomoses.
Lasers in Medical Science, 2018
Although low-level laser therapy (LLLT) was discovered already in the 1960s of the twentieth century, it took almost 40 years to be widely used in clinical dermatology/surgery. It has been demonstrated that LLLT is able to increase collagen production/wound stiffness and/or improve wound contraction. In this review, we investigated whether open and sutured wounds should be treated with different LLLT parameters. A PubMed search was performed to identify controlled studies with LLLT applied to wounded animals (sutured incisions-tensile strength measurement and open excisions-area measurement). Final score random effects meta-analyses were conducted. Nineteen studies were included. The overall result of the tensile strength analysis (eight studies) was significantly in favor of LLLT (SMD = 1.06, 95% CI 0.66-1.46), and better results were seen with 30-79 mW/cm 2 infrared laser (SMD = 1.44, 95% CI 0.67-2.21) and 139-281 mW/cm 2 red laser (SMD = 1.52, 95% CI 0.54-2.49). The overall result of the wound contraction analysis (11 studies) was significantly in favor of LLLT (SMD = 0.99, 95% CI 0.38-1.59), and the best results were seen with 53-300 mW/cm 2 infrared laser (SMD = 1.18, 95% CI 0.41-1.94) and 25-90 mW/cm 2 red laser (SMD = 1.6, 95% CI 0.27-2.93). Whereas 1-15 mW/ cm 2 red laser had a moderately positive effect on sutured wounds, 2-4 mW/cm 2 red laser did not accelerate healing of open wounds. LLLT appears effective in the treatment of sutured and open wounds. Statistical heterogeneity indicates that the tensile strength development of sutured wounds is more dependent on laser power density compared to the contraction rate of open wounds.
Veterinary Surgery, 2018
Objective: To determine the effects of low-level laser therapy (LLLT) on primarily closed incisions and full thickness open wounds in dogs. Study design: Prospective, masked, placebo-controlled design. Animal population: Healthy intact female dogs (n 5 10). Methods: Dogs underwent bilateral flank ovariectomy procedures, and open wounds were created bilaterally with a punch biopsy. Each side of the dog (incision and open wound) was randomly assigned to the treatment (TX) group or the control (CN) group. The TX group received LLLT once daily for 5 days with a 980-nm laser and a total energy density of 5 J/cm 2. The CN group received a sham treatment (laser turned off) for an identical amount of time each day. The wounds were assessed visually; measured; photographed at postoperative days 3, 7, 11, and 14; and biopsied on postoperative days 7 and 14. A 2-way repeated measures multivariate analysis of variance was used to analyze differences between groups. Results: There was no difference between groups for subjective assessment of healing time and wound measurements (P 5 .7). There was no difference in histopathologic assessment except that the CN group had more necrosis and perivascular lymphocytes and macrophages at day 7 (P 5 .03). The TX group had more perivascular lymphocytes and macrophages at day 14 (P 5 .01). Conclusion: LLLT did not appear to influence the healing of surgically created incisions and small wounds with the methodology reported here. Clinical significance: Results of this study do not support recommending LLLT to stimulate healing of uncomplicated, small wounds and incisions.
… and Laser Surgery, 2010
Objectives: To analyze the effects of low-level laser therapy (LLLT), 670 nm, with doses of 4 and 7 J/cm 2 , on the repair of surgical wounds covered by occlusive dressings. Background Data: The effect of LLLT on the healing process of covered wounds is not well defined. Materials and Methods: For the histologic analysis with HE staining, 50 male Wistar rats were submitted to surgical incisions and divided into 10 groups (n ¼ 5): control; stimulated with 4 and 7 J/cm 2 daily, for 7 and 14 days, with or without occlusion. Reepithelization and the number of leukocytes, fibroblasts, and fibrocytes were obtained with an image processor. For the biomechanical analysis, 25 rats were submitted to a surgical incision and divided into five groups (n ¼ 5): treated for 14 days with and without occlusive dressing, and the sham group. Samples of the lesions were collected and submitted to the tensile test. One-way analysis of variance was performed, followed by post hoc analysis. A Tukey test was used on the biomechanical data, and the Tamhane test on the histologic data. A significance level of 5% was chosen (p 0.05). Results: The 4 and 7J/cm 2 laser with and without occlusive dressing did not alter significantly the reepithelization rate of the wounds. The 7 J/cm 2 laser reduced the number of leukocytes significantly. The number of fibroblasts was higher in the groups treated with laser for 7 days, and was significant in the covered 4 J/cm 2 laser group. Conclusions: Greater interference of the laser-treatment procedure was noted with 7 days of stimulation, and the occlusive dressing did not alter its biostimulatory effects.
Endovenous laser treatment: a morphological study in an animal model
Phlebology / Venous Forum of the Royal Society of Medicine, 2009
The destruction induced during endovenous laser treatment (ELT) of the saphenous vein and the perivenous tissue in an animal model (goats) was analysed. Differences in vein wall destruction produced by two laser types, the 980 and 1500 nm diode lasers, were evaluated histologically. In 14 goats, 28 lateral saphenous veins were treated with ELT. In 14 veins we used the 980 nm diode laser and in the remnant a 1500 nm laser. Postoperatively the veins were removed at different stages and sent for histological examination. Immediately removed veins after ELT show an uneven destruction of the vein wall. Veins harvested one week postoperatively show inflammatory tissue at their periphery. Two and three weeks postoperatively, organization is very extensive. In some cases, recanalization begins in a semi-lunar manner at the contralateral side of the laser hit. Veins treated with a 980 nm laser show deeper ulceration with more perivenous tissue destruction compared with veins treated with a 1...